Jun 17, 2017
The question underlies an inventive and challenging new exhibition in New York that explores the fundamentals of sound and how they relate to the quest to understand the self and the cosmos.
The Rubin Museum of Art, the 13-year-old institution devoted to India and the Himalayas, shakes off the visual bias of most exhibitions. Instead, visitors to “The World Is Sound,” which opened Friday and runs until January 8, enter with their ears.
While the exhibition showcases visual artifacts, such as an 18th-century trumpet made of human leg-bone played in Tibetan funerals, the focus is on actual sound, which can be felt powerfully by putting on headphones, touching wall panels, or even walking the spiraling six-floor staircase.
The highlight is a representation of “Om,” the holy mantra of Hinduism and Buddhism that is said to encompass all possible sounds — in effect, the universe itself.
In the months before the exhibition, the Rubin Museum, in New York's Chelsea neighborhood, asked visitors to stop by a small recording studio and chant “Om.”
It collected 10,000 files and, through software, set them on three pitches to merge together into an hour-long “Collective Om” that plays continually in a meditation room with three-dimensional sound.
Hearing the Big Bang
Outer space is silent, with no air to carry the vibrations that cause sound. But the exhibition, expanding on the “Om” concept, asks artists to imagine the sound heard in the vibrations from the Big Bang, the sudden expansion of matter considered by astrophysicists to mark the birth of the universe.
C. Spencer Yeh, the Taiwanese-born artist who led the section, imagined a trio of 45 diverse and shifting computerized voices that say the letters “A,” “U,” and “M,” which merge continuously together.
New York-born artist Samita Sinha's work builds off a recitation of the Hindi alphabet. Another piece, by artist Jules Gimbrone, records and re-records a reciting of a text through a four-foot (1.2-meter) vessel of salt water until the voice is unrecognizable.
Yeh said he gave loose guidelines to the artists on imagining the sound of creation. Still, he was struck that almost all of the artists chose to use the human voice.
The exhibition also offers introductions into late experimental composer Pauline Oliveros's concept of “deep listening,” which involves fully letting go to take in the sound of the environment.
Impermanence of sound
With sound just a matter of vibrations, does music have permanence?
The impermanence of sound is reflected at death in Tibetan custom. Visitors at the exhibition are invited to lie supine on a bench to hear recitations of the Tibetan Book of the Dead, which describe experiences in bardo, a sort of limbo between death and rebirth.
The book encourages the listener to channel positive energy, warning that a slip into darkness in the transient state could doom the journey to the next life.
Read more at Discovery News
The space-based technique developed by the researchers and reported Thursday in the journal Science holds potential for revolutionizing telecommunications and perhaps someday developing a hack-proof internet.
The principle is called quantum entanglement, in which photons or neutrons are created in such a way that they are linked and behave as if they were one entity, even if they are physically separated.
In a groundbreaking experiment led by Professor Jian-Wei Pan of Hefei University in China, a laser on a satellite orbiting 300 miles above Earth produced entangled photons. They were then transmitted to two different ground-based stations 750 miles (1,200 kilometers) apart, without breaking the link between the photons, the researchers said.
That distance is 10 times greater than the previous record for entanglement. The experiment also marked the first time entangled photons were generated in space. Both stations are in the mountains of Tibet, at a height that reduced the amount of air the fragile photons had to traverse.
“It's a huge, major achievement,” Thomas Jennewein, physicist at the University of Waterloo in Canada, told Science. “They started with this bold idea and managed to do it.”
Entangled particles hold the promise of creating a communications system that can send secure messages without cables, signals, or code: any action on one of the twins is detected by the other, so the message sent along such a conduit can't be hacked.
Those properties of quantum physics also hold the potential for super-fast computers.
American and European teams are considering sending quantum-based equipment to the International Space Station. One test would see whether changing gravitational fields affect entanglement.
Read more at Discovery News
Jun 16, 2017
|This is the first study to make a direct connection between birth outcomes and placental oxygen transport.|
The study, published in Scientific Reports is the first to make a direct connection between birth outcomes and placental oxygen transport.
By studying identical twins, the researchers were uniquely able to control for both genetic factors and maternal risk factors. Although identical twins also share a placenta, it is divided into two separate compartments, and one may be healthier than the other.
P. Ellen Grant, MD, director of Boston Children's Fetal-Neonatal Neuroimaging and Developmental Science Center, and Elfar Adalsteinsson, PhD at MIT have developed a noninvasive method that uses MRI to map the timing of oxygen delivery across the placenta in real time. Using this technique, called Blood-Oxygenation-Level-Dependent (BOLD) MRI, they showed that dysfunctional placentas have large regions with slow oxygen transport to the fetus.
"Until now, we had no way to look at regional placental function in vivo," says Grant. "Prenatal ultrasound or routine clinical MRI can assess placental structure, but cannot assess regional function, which is not uniform across the placenta. Doppler ultrasound, the current clinical method of assessing placental function, measures blood flow in the umbilical arteries and other fetal vessels, but it cannot tell how well oxygen or nutrients are being transported from mother to fetus."
Real-time placental oxygen mapping
In the new study, part of the NIH-funded Human Placenta Project, Grant, co-senior investigator Julian Robinson, MD, chief of obstetrics at Brigham and Women's Hospital (BWH), and their colleagues followed seven sets of identical twins all the way to birth, specifically tracking pregnancies in which one twin was smaller than the other.
At 29 to 34 weeks of pregnancy, the seven mothers underwent BOLD MRI for about 30 minutes. While they inhaled pure oxygen for 10-minute stretches, Grant's team measured how long it took oxygen to reach its maximum concentration in the placenta, known as the time to plateau (TTP), and then how long it took for the oxygen to pass through the umbilical cord into the fetus and penetrate the brain and liver. Researchers led by Polina Golland, PhD, at MIT CSAIL used image-correction algorithms developed by MIT to adjust for fetal motion.
They found that a longer TTP in the placenta correlated with lower liver and brain volumes and lower newborn birth weights. TTP also correlated with placental pathology when placentas were examined after birth by placental pathologist Drucilla Roberts, MD, at Massachusetts General Hospital (MGH).
Grant hopes her team's work will be used to better understand pregnancy risk factors, develop a prenatal test for mothers in whom placental dysfunction is suspected and ultimately improve prenatal care. "Our next goal is to figure out what causes variation in oxygen transport in the placenta and identify a cutoff value that would be of concern in a pregnancy, including singleton pregnancies," she says. "Then, we can think about potential treatments to improve placental oxygen transport, and use our methods to immediately assess the success of these treatments."
Grant believes placental oxygen transport is a prime example of how environmental factors can modify the DNA we all inherit. Future studies will investigate how placental oxygen transport affects fetal gene expression and specific measures of brain development and organ metabolism. These studies will use a special MRI coil to improve image accuracy, developed for pregnant mothers by collaborator Larry Wald, PhD, at the Athinoula A. Martinos Center. William Barth, MD, chief of Maternal-Fetal Medicine at MGH and Chloe Zera, MD, MPH, a BWH obstetrician, have also joined the team to guide the development of novel MR imaging strategies to improve the management of pregnant mothers.
Read more at Science Daily
"Our color vision is very strange," says James Higham, an assistant professor in NYU's Department of Anthropology and one of the study's co-authors. "Our green receptor and our red receptor detect very similar colors. One would think that the ideal type of color vision would look different from ours, and when we design color detection, such as for digital cameras, we construct a different type of color vision. However, we've now shown that when it comes to spotting changes in color linked to social cues, humans outshine the type of color vision we've designed for our technologies."
The study, which appears in the journal Proceedings of the Royal Society Biological Sciences, focuses on trichromatic color vision -- that is, how we process the colors we see, based on comparisons among how red, green, and blue they are.
One particularly interesting thing about how our visual system is structured is how significantly it differs from that of cameras. Notably, the green and red photoreceptors we use for color vision are placed very close together; by contrast, the equivant components in cameras are situated with ample (and even) spacing among them. Given that cameras are designed to optimally capture color, many have concluded that their ability to detect an array of colors should be superior to that of humans and other primates -- and wondered why our vision is the way it is.
One idea that has been well-studied is related to foraging. It hypothesizes that primate color vision allows us to detect between subtle shades of green and red, which is useful, for example, when fruit are ripening against green leaves in a tree. An alternative hypothesis relates to the fact that both humans and primates must be able to spot subtle changes in facial color in social interactions. For instance, some species of monkeys give red signals on their faces and on genitals that change color during mating and in social interactions. Similarly, humans exhibit facial color changes such as blushing, which are socially informative signals.
In their study, the researchers had 60 human subjects view a series of digital photographs of female rhesus macaque monkeys. These primates' facial color has been known to change with their reproductive status, with female faces becoming redder when they are ready to mate. This process, captured in the series of photographs, provides a good model for testing the ability to not only detect colors, but also to spot those linked to social cues -- albeit across two species.
In different sets of photographs, the scientists developed software that replicated how colors look under different types of color vision, including different types of color blindness, and the type of trichromatic vision seen in many artificial systems, with even spacing of the green and red photoreceptors. Some of the study's subjects viewed photos of the transformation of the monkeys' faces as a human or primate would see them while others saw pictures as a color-blind person would and others as a camera would. During this period, the study's subjects had to discriminate between the different colors being exhibited by the monkeys in the photos.
Overall, the subjects viewing the images using the human/primate visual system more accurately and more quickly identified changes in the monkeys' face coloring.
"Humans and many other primates have an unusual type of color vision, and no one is sure why," first author Chihiro Hiramatsu of Japan's Kyushu University notes. "Here, we provide one of the first experimental tests of the idea that our unusual vision might be related to detecting social signals in the faces of others."
Read more at Science Daily
"Our concept of what a magma reservoir looks like has to change," said Kari Cooper, professor of earth and physical sciences at the University of California, Davis and corresponding author on the paper.
It's hard to study magma directly. Even at volcanic sites, it lies miles beneath the Earth's surface and while geologists have occasionally drilled into magma by accident or design, heat and pressure destroy any instrument you could try to put into it.
Instead, Cooper and her colleagues collected zircon crystals from debris deposited around Mount Tarawera in New Zealand by an eruption about 700 years ago. That eruption, roughly five times the size of Mount St. Helens in 1980, brought lava to the surface that had resided in the reservoir, exposed to its temperature and chemistry. Once on the surface, that record of the past was frozen in place.
The crystals are like a "black box" flight recorder for studying volcanic eruptions, Cooper said. "Instead of trying to piece together the wreckage, the crystals can tell us what was going on while they were below the surface, including the run up to an eruption."
By studying trace components elements within seven zircon crystals, they could determine when the crystals first formed and how long during their life within the magma reservoir they were exposed to high heat (over 700 degrees Celsius). The crystals give information about the state of the part of the magma reservoir in which they resided.
The researchers found that all but one of the seven crystals were at least tens of thousands of years old, but had spent only a small percentage (less than about four percent) exposed to molten magma.
A Snow Cone Not a Molten Lake
The picture that emerges, Cooper said, is less a seething mass of molten rock than something like a snow cone: mostly solid and crystalline, with a little liquid seeping through it.
To create an eruption, a certain amount of that solid, crystalline magma has to melt and mobilize, possibly by interacting with hotter liquid stored elsewhere in the reservoir. The pre-eruption magma likely draws material from different parts of the reservoir, and it happens very quickly in geological time -- over decades to centuries. That implies that it may be possible to identify volcanoes at highest risk of eruption by looking for those where the magma is most mobile.
Interestingly, all the crystals studied had remained unmelted in Mount Tarawera's magma reservoir through a gigantic eruption that occurred about 25,000 years ago, before being blown out in the smaller eruption 700 years ago. That shows that magma mobilization must be a complex process.
Read more at Science Daily
|This is a Louisiana subsidence map.|
The map, published in GSA Today, has long been considered the "holy grail" by researchers and policy makers as they look for solutions to the coastal wetland loss crisis, the researchers said.
"The novel aspect of this study is that it provides a map that shows subsidence rates as observed at the land surface," said Torbjörn Törnqvist, professor of geology and chair of the Department of Earth and Environmental Sciences at Tulane University.
"This sets it apart from previous attempts to map subsidence rates."
Jaap Nienhuis, a postdoctoral fellow in earth and environmental sciences, is the lead author of the study. He said that while the present-day subsidence rate averages about nine millimeters, or just over a third of an inch each year, there is plenty of variability among specific sites along the coast.
"This information will be valuable for policy decisions about coastal restoration, such as planning of large sediment diversions that are intended to make portions of Louisiana's coast more sustainable," Nienhuis said.
The researchers used data obtained by a network of hundreds of instruments known as surface-elevation tables, scattered along the Louisiana coast. These instruments enabled the Tulane team to calculate subsidence rates in the shallow subsurface (up to about 10 meters or 30 feet depth) where most of the subsidence happens. This large network of surface-elevation tables was installed during the post-Katrina period, so determining subsidence rates with this method has only recently become possible.
From Science Daily
|AWARE instruments at the WAIS Divide field camp in central West Antarctica in December 2015 under a spectacular optical display ("sun dog") due to atmospheric ice crystals.|
In the June 15 issue of the journal Nature Communications, they report that the warm spell persisted for more than two weeks in January 2016. Satellite data revealed a mix of melted snow and ice over most of the Ross Ice Shelf -- a thick platform of floating ice that channels about a third of the ice flowing from the West Antarctic Ice Sheet into the ocean.
While researchers have been gathering evidence for years that warm ocean water is melting West Antarctic ice shelves from beneath, this is one of the first times they've been able to document how warm air could also cause widespread melting from above.
As it happens, researchers had installed the necessary instruments to investigate these processes in West Antarctica only a few weeks earlier, as part of a study to better understand how clouds affect the amount of energy that reaches the snow surface and influence its temperature.
"We were extraordinarily fortunate to be able to deploy state-of-the art equipment to West Antarctica just before this large melt event occurred," said Dan Lubin, principal investigator of the Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment (AWARE). Lubin is a research physicist at the Scripps Institution of Oceanography in La Jolla, California and a coauthor of the Nature Communications study.
"These atmospheric measurements will help geophysical scientists develop better physical models for projecting how the Antarctic ice sheet might respond to a changing climate and influence sea level rise," Lubin added.
Julien Nicolas, lead author of the paper, is a research associate at the Byrd Polar and Climate Research Center (BPCRC) at The Ohio State University. He's part of the OSU team that provides weather and climate analysis for AWARE.
When Nicolas got a January 2016 alert from the AWARE expedition that the weather at their campsite atop of the West Antarctic Ice Sheet had turned unseasonably warm, he checked to see in the satellite data what was happening to the rest of West Antarctica.
The presence of water in the snow is often hard to detect from visible satellite imagery, especially if clouds block the view. Instead, Nicolas analyzed satellite measurements of the microwave radiation emitted by the snowpack, since dry and wet snows have very different microwave signatures.
What he saw during the melting event was an area of roughly 300,000 square miles, including most of the Ross Ice Shelf, that likely contained a mix of snow and water.
"What probably happened is that the surface snowpack was able to contain the meltwater, acting as a buffer and preventing the formation of melt ponds and streams that can be common on some Antarctic ice shelves," Nicolas said, "but we cannot rule out the presence of standing water in many locations."
What makes this event particularly interesting to scientists is that it took place during one of the strongest El Nino events on record.
"This conjunction of events was no coincidence," he said.
During an El Nino, warm waters from the equatorial Pacific Ocean move east. El Ninos also favor weather patterns that steer warm air towards West Antarctica, but strong westerly winds that blow over the ocean to the north of the continent usually keep the warmer air at bay.
BPCRC senior research associate Aaron Wilson, also a coauthor on the study, used climate models to show that melt events in West Antarctica are more likely to occur during El Nino conditions, especially when westerly winds are weak. What makes this January 2016 event unique, he explained, is that the warming occurred despite strong westerly winds.
"Without the strong westerlies, it's likely there would have been much more melting," Wilson said.
Read more at Science Daily
Jun 15, 2017
|A ribbon of ammonia -- a tracer of star-forming gas -- in the Orion Nebula as seen with the GBT (orange). Background image in blue is a WISE telescope infrared image showing the dust in the region.|
The researchers used the National Science Foundation's (NSF) Green Bank Telescope (GBT) in West Virginia to study a 50 light-year long filament of star-forming gas that is wending its way through the northern portion of the OMC known as Orion A.
The GBT rendered this image by detecting the faint radio signals naturally emitted by molecules of ammonia that suffuse interstellar clouds. Scientists study these molecules to trace the motion and temperature of vast swaths of star-forming gas.
These observations are part of the first data release from a large campaign known as the Green Bank Ammonia Survey. Its purpose is to map all of the star-forming ammonia and other key tracer molecules in a massive structure known as the Gould Belt.
The Gould Belt is an extended ribbon of bright, massive stars stretching about 3,000 light-years in an arc across the sky. This first release covers four distinct Gould Belt clouds, one located in Taurus, one in Perseus, one in Ophiuchus, and Orion A North in Orion.
"We hope to use these data to understand better how large clouds of gas in our galaxy collapse to form new stars," said Rachel Friesen, one of the collaboration's co-principal investigators and, until 31 May 2017, a Dunlap Fellow at the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto in Canada. "The new data are critical to assessing whether certain gas clouds and filaments are stable and enduring features or if they are undergoing collapse and forming new stars."
Prior ammonia observations by many of the survey's co-authors have targeted smaller portions of similar star-forming clouds. In these individual studies, the researchers identified sharp transitions in the amount of turbulence between the larger cloud and the smaller-scale star-forming cores, studied the stability against gravitational collapse of the gas within a young protocluster, and investigated how mass builds up along gas filaments and flows into stellar cluster-forming regions.
"These data provide a unique view of the cold dense gas involved in forming stars like our sun," said Jaime E. Pineda, the collaboration's other co-principal investigator, with the Max-Planck Institute for Extraterrestrial Physics in Garching, Germany. "We hope they can also help us determine how much rotation is present in the regions that will form stars; this is crucial to understand how protoplanetary disks are formed."
The new GBT image is combined with an infrared one taken with NASA's Wide-field Infrared Survey Explorer (WISE) telescope. The composite image illustrates how star-forming gas in this region relates to the bright stars and dark, dusty regions of the nebula.
The 100-meter GBT, which is located in the National Radio Quiet Zone, is exquisitely sensitive and uniquely able to study the molecular composition of star-forming clouds and other objects in the cosmos. Future observations of the Gould Belt will provide greater insights into the conditions that give rise to stars like our sun and planets like Earth.
Read more at Science Daily
|This is an artistic reconstruction and skeleton made by Voltaire Paes Neto.|
Aleodon is a genus of probainognathian cynodont, a taxon which evolved in the Triassic period, co-existed with dinosaur precursors and other archosaurs and eventually gave rise to mammals. The Aleodon genus was first described using fossils from Tanzania and Namibia, but it was not clear if it belonged within the family of carnivorous mammal-like reptiles known as Chiniquodontids, which includes the morphologically similar Chiniquodon.
The authors of the present study examined the skulls, jaws and teeth of Middle-Late Triassic fossil specimens from the Dinodontosaurus Assemblage Zone in Rio Grande do Sul, Brazil, most of which were previously thought to be Chiniquodontids, and compared them to a known African Aleodon species, A. brachyrhamphus.
The researchers used tooth morphology to identify one of the specimens as a new Aleodon species, which they named A. cromptoni after Dr Alfred "Fuzz" Crompton, who described the Aleodon genus. They also identified as Aleodon seven Brazilian specimens, previously thought to be chiniquodontids or traversodontids, and possibly one Namibian specimen, noting that this may call the reliability of Chiniquodon identification into question. Phylogenetic analysis indicated that Aleodon cromptoni may be, as suspected, a species in the Chiniquodonidae family.
Whilst the analysis was limited by the partial nature of some of the specimens, the authors note that the identification of these Late Triassic Aleodon specimens in Brazil strengthens the correlation between probainognathians from this epoch in South America and in Africa.
From Science Daily
|Red Sea Sponge.|
The fossil record reveals that almost all of the animal phyla known today had come into existence by the beginning of the Cambrian Period some 540 million years ago. The earliest known animal fossils already exhibit complex morphologies, which implies that animals must have originated long before the onset of the Cambrian. However, taxonomically assignable fossils that can be confidently dated to pre-Cambrian times are very rare. In order to determine what the root of their family tree looked like, biologists need reliable dating information for the most ancient animal subgroups -- the sponges, cnidarians, comb jellies and placozoans. Dr. Martin Dohrmann and Professor Gert Wörheide of the Division of Palaeontology and Geobiology in the Department of Earth and Environmental Sciences at Ludwig-Maximilians-Universitaet (LMU) in Munich have now used a new strategy based on the so-called molecular-clock to investigate the chronology of early animal evolution and produce a new estimate for the ages of the oldest animal groups. Their findings appear in the journal Scientific Reports.
The molecular clock approach is based on the principle that mutations accumulate in the genomes of all organisms over the course of time. The extent of the genetic difference between two lineages should therefore depend on the time elapsed since they diverged from their last common ancestor. "Our study is based on a combination of genetic data from contemporary animals and information derived from well dated fossils, which we analyzed with the help of complex computer algorithms," Dohrmann explains. For the study, the researchers used an unusually large dataset made up of the sequences of 128 proteins from 55 species, including representatives of all the major animal groups, focusing in particular on those that diverged very early.
The analysis confirms the conclusion reached in an earlier study, which dated the origin of animals to the Neoproterozoic Era, which lasted from 1000 to 540 million years ago. However, much to their surprise, the results also suggested that the earliest phyla, and the ancestors of all bilateral animal species (the so-called Bilateria), originated within the -- geologically speaking -- short time-span of 50 million years. "In addition, this early phase of evolutionary divergence appears to have preceded the extreme climate changes that led to Snowball Earth, a period marked by severe long-term global glaciation that lasted from about 720 to 635 million years ago," Dohrmann says. In order to assess the plausibility of the new findings, the researchers plan to carry out further analyses using more extensive datasets and improved statistical methods." To arrive at well-founded conclusions with respect to the morphology and ecology of the earliest animals, we also need to know more about the environmental conditions that prevailed during the Neoproterozoic, and we need more fossils that can be confidently assigned to specific taxonomic groups," Wörheide says.
From Science Daily
|This is an artist impression of chaotic magnetic field lines very near a newly emerging protostar.|
Now, a team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has discovered a surprisingly weak and wildly disorganized magnetic field very near a newly emerging protostar. These observations suggest that the impact of magnetic fields on star formation is more complex than previously thought.
The researchers used ALMA to map the magnetic field surrounding a young protostar dubbed Ser-emb 8, which resides about 1,400 light-years away in the Serpens star-forming region. These new observations are the most sensitive ever made of the small-scale magnetic field surrounding a young protostar. They also provide important insights into the formation of low-mass stars like our own sun.
Previous observations with other telescopes found that magnetic fields surrounding some young protostars form a classic "hourglass" shape -- a hallmark of a strong magnetic field -- that starts near the protostar and extends many light-years into the surrounding cloud of dust and gas.
"Before now, we didn't know if all stars formed in regions that were controlled by strong magnetic fields. Using ALMA, we found our answer," said Charles L. H. "Chat" Hull, an astronomer and NRAO Jansky Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., and lead author on a paper appearing in the Astrophysical Journal Letters. "We can now study magnetic fields in star-forming clouds from the broadest of scales all the way down to the forming star itself. This is exciting because it may mean stars can emerge from a wider range of conditions than we once thought."
ALMA is able to study magnetic fields at the small scales inside star-forming clumps by mapping the polarization of light emitted by dust grains that have aligned themselves with the magnetic field.
By comparing the structure of the magnetic field in the observations with cutting-edge supercomputer simulations on multiple size scales, the astronomers gained important insights into the earliest stages of magnetized star formation. The simulations -- which extend from a relatively nearby 140 astronomical units (an astronomical unit is the average distance from Earth to the sun) from the protostar to as far out as 17 light-years -- were performed by CfA astronomers Philip Mocz and Blakesley Burkhart, who are co-authors on the paper.
In the case of Ser-emb 8, the astronomers think they have captured the original magnetic field around the protostar "red handed," before outflowing material from the star could erase the pristine signature of the magnetic field in the surrounding molecular cloud, noted Mocz.
Read more at Science Daily
Adiël Klompmaker was struck by a similar idea a few years ago, when he was a postdoctoral researcher at the Florida Museum of Natural History. He was preparing a database of drill holes created by marine predators in shells, and it occurred to him that the shells had untapped potential as “smoking gun” evidence for over 500 million years of marine predator-prey interactions.
He and his colleagues have since conducted a detailed analysis of thousands of such shells, revealing that numerous marine predators have grown steadily larger and more powerful over time, while their preferred prey has remained relatively small.
The findings, reported in the journal Science, support what is known as the “escalation hypothesis.” This theory, in part, holds that increasingly powerful and metabolically active animals at the top of the food chain can drive evolutionary trends in their prey, such as by affecting their defensive arsenals and ability to move.
“There is a long-term increase throughout the last 500 million years in the size of drilling predators and predator-prey size ratios of drilling predators and their prey,” said Klompmaker, who is now a postdoctoral researcher at the University of California, Berkeley.
“Although prey size did not increase or decrease over the last 500 million years, they may have responded to their predators by becoming more mobile,” he added. “Some of them started to burrow into the bottom of the oceans, and some developed a more fortified shell.”
The researchers next compiled data from 6943 drilled shells to examine trends in the size of drill holes, prey size, and predator-prey size ratios from the Cambrian Period (541–485.5 million years ago) to the present. The difference in size ratios increased 67-fold, providing evidence for the ever-widening gap in size between certain big marine predators and their tiny prey.
Klompmaker and senior author Seth Finnegan of UC Berkeley explained that a combination of three factors likely led to the increase in predator size and predator-prey size ratios. First, the density of prey items increased over time, such that predators encountered prey more often and with less search effort.
“Secondly, the amount of meat per shell rose as the relatively less nutritious brachiopods declined in abundance and the meatier mollusks increased in abundance over time,” Finnegan said.
Humans are part of the equation now, but the researchers are not yet certain what affect we are having on the escalation hypothesis.
“Marine predators, especially big ones, have been particularly vulnerable to human exploitation, including many large predatory fish and multiple groups of crustaceans, however, how these threats impact drilling predators such as moon snails is more difficult to evaluate,” co-author Michal Kowalewski of the Florida Museum of Natural History said. “In fact, it is possible that the decline of higher level predators, some of which prey on predatory mollusks, may benefit drilling predators.”
“On the other hand,” he added, “many recent environmental changes negatively affect all benthic organisms, so the long-term impact of humans is difficult to predict.”
Read more at Discovery News
Jun 14, 2017
Astronomers have long known that galaxies cluster together into enormous systems -- the urban centers of the cosmos -- and that the largest galaxies tend to 'point' towards their neighbors. But how and when these alignments occur remains a mystery.
Using the Hubble Space Telescope, the international team of collaborators peered across cosmic time to observe 65 distant galaxy clusters whose light has taken billions of years to reach Earth. They showed for the first time that the largest galaxies in these systems were already aligned with their surroundings when the universe was only 1/3 of its current age.
"Our results show that galaxy alignments were established very early in the universe's history. It's an important new piece to the puzzle because it says that whatever caused the alignments, it acted quickly," says De Propris.
Although clusters have hundreds or thousands of member galaxies, most are randomly oriented in space. Only the biggest galaxies are aligned with their surroundings, which suggests that they are especially sensitive to their environment.
The team is eager to look further back in time by observing more remote clusters. But studying galaxies at the dawn of the time is not easy, even with Hubble.
Read more at Science Daily
|A stone tool thought to be a speartip made from radiolarite sourced over 100km to the east of the cave.|
An archaeological dig in a cave in the Moravian region of the Czech Republic has provided a timeline of evidence from 10 sedimentary layers spanning 28,000 to 50,000 years ago. This is the period when our modern human ancestors first arrived in Europe.
The dig, in a cave near the Czech border with Austria and around 150kms north of Vienna, has unearthed over 20,000 animal bones as well as stone tools, weapons and an engraved bone bead that is the oldest of its kind in Central Europe.
ANU archaeologist Dr Duncan Wright said the project was so important because it gives some of the earliest evidence of modern human activity in the region. This was a period when humans were moving substantial distances and bringing with them portable art objects.
"In the early layers the items we've found are locally made flakes, possibly used by small communities living and hunting in the vicinity to kill animals or prepare food, but around 40,000 years ago we start to see objects coming from long distances away," Dr Wright said.
"Dating from this same time we unearthed a bead made from mammal bone. This is the oldest portable art object of its type found anywhere in central Europe and provides evidence of social signalling, quite possibly used as a necklace to mark the identity of the wearer.
"So between these two periods, we've either seen a change in behaviour and human movement or possibly even a change in species."
Archaeologist Ladislav Nejman of the University of Sydney said one of the biggest questions is the beginnings of human exploration of this landscape by Homo sapiens who arrived in this area for the first time. "We've found that somewhere between 40-48,000 years ago people became highly mobile," Dr Nejman said.
"Instead of moving short distances near the cave where they lived, they were walking for hundreds of kilometres quite often. We know that because we found various artefacts where the raw material comes from 100-200 kilometres away.
"The artefacts were also made of different materials from different regions. Some from the North-West, some from the North, some from the East."
However in layer 10, which represents an earlier time period between 48-45,000 years ago, all the recovered stone artefacts were made using local raw material, which indicates that the high residential mobility came later.
Dr Nejman said the study also revealed valuable new information about the climate of the region.
"We haven't had such a long sequence of sedimentary layers before that we could test," he said.
"The climate changed quite often from warmer to colder, and vice versa, but at all times it was much colder than the interglacial period that we have lived in for the past 10,000 years."
Samples from the site have been sent through for analysis using a new technique, called ancient sediment DNA analysis. This is the first scientific method that can detect which species were present even without the bones of these species. It tests remnant DNA preserved in the sediment.
Dr Wright said the results will shed new light on a period of transition between two species of humans and also give clearer evidence about the activities of our modern human ancestors in a period and region where little is known.
"We can tell by the artefacts that small groups of people camped at this cave. This was during glacial periods suggesting they were well adapted to these harsh conditions" Dr Wright said.
Read more at Science Daily
|This is a radio image of a very young binary star system, less than about 1 million years old, that formed within a dense core (oval outline) in the Perseus molecular cloud. All stars likely form as binaries within dense cores.|
Almost certainly yes -- though not an identical twin. And so did every other sunlike star in the universe, according to a new analysis by a theoretical physicist from the University of California, Berkeley, and a radio astronomer from the Smithsonian Astrophysical Observatory at Harvard University.
Many stars have companions, including our nearest neighbor, Alpha Centauri, a triplet system. Astronomers have long sought an explanation. Are binary and triplet star systems born that way? Did one star capture another? Do binary stars sometimes split up and become single stars?
Astronomers have even searched for a companion to our sun, a star dubbed Nemesis because it was supposed to have kicked an asteroid into Earth's orbit that collided with our planet and exterminated the dinosaurs. It has never been found.
The new assertion is based on a radio survey of a giant molecular cloud filled with recently formed stars in the constellation Perseus, and a mathematical model that can explain the Perseus observations only if all sunlike stars are born with a companion.
"We are saying, yes, there probably was a Nemesis, a long time ago," said co-author Steven Stahler, a UC Berkeley research astronomer.
"We ran a series of statistical models to see if we could account for the relative populations of young single stars and binaries of all separations in the Perseus molecular cloud, and the only model that could reproduce the data was one in which all stars form initially as wide binaries. These systems then either shrink or break apart within a million years."
In this study, "wide" means that the two stars are separated by more than 500 astronomical units, or AU, where one astronomical unit is the average distance between the sun and Earth. A wide binary companion to our sun would have been 17 times farther from the sun than its most distant planet today, Neptune.
Based on this model, the sun's sibling most likely escaped and mixed with all the other stars in our region of the Milky Way galaxy, never to be seen again.
"The idea that many stars form with a companion has been suggested before, but the question is: how many?" said first author Sarah Sadavoy, a NASA Hubble fellow at the Smithsonian Astrophysical Observatory. "Based on our simple model, we say that nearly all stars form with a companion. The Perseus cloud is generally considered a typical low-mass star-forming region, but our model needs to be checked in other clouds."
The idea that all stars are born in a litter has implications beyond star formation, including the very origins of galaxies, Stahler said.
Stahler and Sadavoy posted their findings in April on the arXiv server. Their paper has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.
Stars birthed in 'dense cores'
Astronomers have speculated about the origins of binary and multiple star systems for hundreds of years, and in recent years have created computer simulations of collapsing masses of gas to understand how they condense under gravity into stars. They have also simulated the interaction of many young stars recently freed from their gas clouds. Several years ago, one such computer simulation by Pavel Kroupa of the University of Bonn led him to conclude that all stars are born as binaries.
Yet direct evidence from observations has been scarce. As astronomers look at younger and younger stars, they find a greater proportion of binaries, but why is still a mystery.
"The key here is that no one looked before in a systematic way at the relation of real young stars to the clouds that spawn them," Stahler said. "Our work is a step forward in understanding both how binaries form and also the role that binaries play in early stellar evolution. We now believe that most stars, which are quite similar to our own sun, form as binaries. I think we have the strongest evidence to date for such an assertion."
According to Stahler, astronomers have known for several decades that stars are born inside egg-shaped cocoons called dense cores, which are sprinkled throughout immense clouds of cold, molecular hydrogen that are the nurseries for young stars. Through an optical telescope, these clouds look like holes in the starry sky, because the dust accompanying the gas blocks light from both the stars forming inside and the stars behind. The clouds can, however, be probed by radio telescopes, since the cold dust grains in them emit at these radio wavelengths, and radio waves are not blocked by the dust.
The Perseus molecular cloud is one such stellar nursery, about 600 light-years from Earth and about 50 light-years long. Last year, a team of astronomers completed a survey that used the Very Large Array, a collection of radio dishes in New Mexico, to look at star formation inside the cloud. Called VANDAM, it was the first complete survey of all young stars in a molecular cloud, that is, stars less than about 4 million years old, including both single and multiple stars down to separations of about 15 astronomical units. This captured all multiple stars with a separation of more than about the radius of Uranus' orbit -- 19 AU -- in our solar system.
Stahler heard about the survey after approaching Sadavoy, a member of the VANDAM team, and asking for her help in observing young stars inside dense cores. The VANDAM survey produced a census of all Class 0 stars -- those less than about 500,000 years old -- and Class I stars -- those between about 500,000 and 1 million years old. Both types of stars are so young that they are not yet burning hydrogen to produce energy.
Sadavoy took the results from VANDAM and combined them with additional observations that reveal the egg-shaped cocoons around the young stars. These additional observations come from the Gould Belt Survey with SCUBA-2 on the James Clerk Maxwell Telescope in Hawaii. By combining these two data sets, Sadavoy was able to produce a robust census of the binary and single-star populations in Perseus, turning up 55 young stars in 24 multiple-star systems, all but five of them binary, and 45 single-star systems.
Using these data, Sadavoy and Stahler discovered that all of the widely separated binary systems -- those with stars separated by more than 500 AU -- were very young systems, containing two Class 0 stars. These systems also tended to be aligned with the long axis of the egg-shaped dense core. The slightly older Class I binary stars were closer together, many separated by about 200 AU, and showed no tendency to align along the egg's axis.
"This has not been seen before or tested, and is super interesting," Sadavoy said. "We don't yet know quite what it means, but it isn't random and must say something about the way wide binaries form."
Egg-shaped cores collapse into two centers
Stahler and Sadavoy mathematically modeled various scenarios to explain this distribution of stars, assuming typical formation, breakup and orbital shrinking times. They concluded that the only way to explain the observations is to assume that all stars of masses around that of the sun start off as wide Class 0 binaries in egg-shaped dense cores, after which some 60 percent split up over time. The rest shrink to form tight binaries.
"As the egg contracts, the densest part of the egg will be toward the middle, and that forms two concentrations of density along the middle axis," he said. "These centers of higher density at some point collapse in on themselves because of their self-gravity to form Class 0 stars."
"Within our picture, single low-mass, sunlike stars are not primordial," Stahler added. "They are the result of the breakup of binaries. "
Their theory implies that each dense core, which typically comprises a few solar masses, converts twice as much material into stars as was previously thought.
Stahler said that he has been asking radio astronomers to compare dense cores with their embedded young stars for more than 20 years, in order to test theories of binary star formation. The new data and model are a start, he says, but more work needs to be done to understand the physics behind the rule.
Read more at Science Daily
The particle, called a charm quark, revealed surprising interactions with its neighboring subatomic particles, measurements show. That discovery could improve scientists' understanding of the conditions that existed soon after the Big Bang, when the universe was permeated by a primordial soup of elementary particles, and possibly show hints of physics beyond what scientists know today.
Back to the beginning
The surprising charm-quark behavior was first spotted at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) in Upton, New York, which aims to recreate conditions in the trillionths of a second after the Big Bang. The key to the new observation is the Heavy Flavor Tracker (HFT), a set of recently installed ultrasensitive photodetectors similar to those in digital cameras. Using the HFT, for the first time, researchers directly measured the behavior of charm quarks as they emerged from the trillion-degree fireball meant to recreate the universe's first moments.
To recreate these primeval conditions, the RHIC fires gold atoms at one another at nearly the speed of light. As they collide, the atoms break up into a soup of elementary, free-flowing particles known as a quark-gluon plasma. Quarks make up more familiar particles, like protons and neutrons, while gluons are the carriers of the strong nuclear force that holds the quarks together.
The measurements tell the physicists whether their models of fields that bind together quarks and gluons, based on a theory called quantum chromodynamics, are correct, according to a new study detailing the findings.
"You can study how nuclear medium behaves and functions at these high temperatures," Brookhaven National Laboratory physicist Flemming Videbaek, a coauthor of the study, told Live Science.
Quarks and their antimatter counterparts come in six varieties, known to physicists as "flavors": up, down, top, bottom, strange and charm. They have different masses; the up and down quarks that make up protons and neutrons are the lightest. Charm quarks are the third heaviest, behind top quarks. They never form in ordinary conditions on Earth; a particle accelerator is necessary to make them.
Albert Einstein's famous E = mc2 equation says energy and mass are the same thing, and when the atomic nuclei collide in the RHIC, the energy is so great that it creates heavier, exotic particles, such as charm quarks.
One of the particles formed by this fiery collision is the D-zero, made up of a charm quark and an anti-up quark. The D-zeros travel for a fraction of a millimeter before they decay and become two other particles: kaons and pions. It's the kaons and pions that the experimenters actually "see" with the HFT.
What surprised the researchers was that the flow of quark-gluon plasma caught the heavy D-zero particles. The football-shaped fireball emitted more D-zeros from the wider part than from the ends, rather than in an evenly distributed way. Previous models predicted that the D-zero, which contains the heavy charm quark, was too massive to interact with the quarks and gluons in the plasma. According to those models, its mass would mean the D-zero barreled out too quickly, before the plasma's forces could act on it, and the plasma would not last long enough to produce much interaction.
Read more at Discovery News
Jun 13, 2017
The website of Winners auction house describes five signed letters written in English between 1951 and 1954.
The site gave current estimates of their combined value as between $31,000 and $46,000.
In a 1951 letter to eminent physicist David Bohm, Einstein discusses Bohm's linkage between quantum theory and "relativistic field theory."
"I must confess that I am not able to guess how such unification could be achieved," Einstein writes.
The typed letter includes an equation added in neat handwriting and the writer's signature.
Bohm, born in the United States to Jewish immigrant parents, had worked with Einstein at Princeton University before fleeing to Brazil after losing his post in Senator Joseph McCarthy's anti-communist witch-hunts.
In a 1954 letter to Bohm, who was living in Sao Paulo, Einstein empathizes with his friend's struggles in his complex theoretical work.
"If God has created the world his primary worry was certainly not to make its understanding easy for us. I feel it strongly since fifty years," he writes.
Winners said the letters came from the estate of Bohm's late widow.
Another 1954 letter refers to the possibility of Bohm moving to Israel, which had been founded in 1948.
Einstein, who had turned down an offer to be the fledgling country's president, believed the time was not ripe for such a move.
"Israel is intellectually alive and interesting but has very narrow possibilities and to go there with the intention to leave on the first occasion would be regretable," he wrote.
Bohm did, in fact, take up a visiting professorship at Israel's renowned Technion technological institute in 1955.
Read more at Discovery News
The gas giant's core had already grown to be 20 times more massive than Earth just 1 million years after the sun formed, a new study suggests.
"Jupiter is the oldest planet of the solar system, and its solid core formed well before the solar nebula gas dissipated, consistent with the core-accretion model for giant planet formation," lead author Thomas Kruijer, of the University of Munster in Germany and Lawrence Livermore National Laboratory in California, said in a statement.
About 4.6 billion years ago, the solar system coalesced from an enormous cloud of gas and dust. The sun formed first, and the planets then accreted from the leftover material spinning around the newborn star in a vast disc.
Theoretical work strongly suggests that Jupiter took shape quite early in the solar system's history, but the planet's precise age had remained a mystery, Kruijer and his colleagues said.
The researchers dated Jupiter's formation and growth by analyzing the ages of certain iron meteorites — shards of the metallic cores of ancient planetary building blocks — that have fallen to Earth. These ages were determined by measuring the abundances of molybdenum and tungsten isotopes. (Isotopes are versions of elements with different numbers of neutrons in their atomic nuclei.)
This work indicated that the meteorites came from two distinct "reservoirs" that were spatially separate for 2 million to 3 million years, beginning about 1 million years after the solar system formed, the researchers said.
"The most plausible mechanism for this efficient separation is the formation of Jupiter, opening a gap in the disk and preventing the exchange of material between the two reservoirs," the researchers wrote in the new study, which was published online today (June 12) in the journal Proceedings of the National Academy of Sciences.
Jupiter's growth rate slowed thereafter, they said. The gas giant didn't reach 50 Earth masses until a minimum of 3 million to 4 million years after the sun's formation, the researchers determined. (Jupiter is currently about 318 times more massive than Earth.)
"Our measurements show that the growth of Jupiter can be dated using the distinct genetic heritage and formation times of meteorites," Kruijer said in the same statement.
Read more at Discovery News
The molecule, methyl isocyanate, “plays an essential role in the formation of proteins, which are basic ingredients for life,” said Victor Rivilla, a scientist at the Astrophysics Observatory in Florence, Italy, and co-author of a study published in Monthly Notices of the Royal Astronomical Society.
The findings could offer clues on how chemicals sparked into living matter on Earth several billion years ago.
At the very least, they show that elements crucial for the emergence of life “were very likely already available at the earliest stage of solar system formation,” said Niels Ligterink, a researcher at Leiden Observatory in the Netherlands and lead author of a second study in the same journal.
Scientists spotted the organic compound in a dense envelope of interstellar dust and gas circling three young stars some 400 light years from Earth in the constellation Ophiuchus, better known as the Serpent Bearer.
Using the Atacama array of radio telescopes in the northern desert of Chile, the two teams independently isolated the chemical signature of methyl isocyanate and then followed up with computer modeling and laboratory experiments to probe the molecule’s origins.
“Thanks to the amazing capabilities of current telescopes, we are discovering more and more complex organic molecules around the birthplaces of stars and planets,” Rivilla told AFP.
Life-giving, but toxic
Scientists also recently detected sugars in space, including a compound called glycolaldehyde, which plays a role in the formation of DNA structure.
Methyl isocyanate beyond our atmosphere was first discovered two years ago, but in a very different context: near complex, high-mass stars many times bigger than the sun. These are not environments that can yield planetary systems like our own.
Earth and the other planets in our solar system formed some 4.5 billion years ago out of matter left over from the sun.
At this very early stage of evolution, the material feeding the formation of the three-star system described Thursday — known prosaically as IRAS 16293-2422 — is rotating in a disk around each star. Some of the gas and dust will fall to the stars, and the rest will make up the planets.
Paradoxically, methyl isocyanate — and other chemical precursors to life — are highly toxic and potentially lethal to humans and other animals.
Read more at Discovery News
Yet despite the critical importance of microbes to life on Earth — and their increasing usefulness in energy production, agriculture, and biotechnology — we still know very little about how they do what they do. That’s because microbes are the most abundant and diverse life forms on the planet, with an estimated billion or more species, only a few thousands of which have been named and identified.
Now a groundbreaking project from the United States Department of Energy (DOE) is attempting to shine light on the unexplored branches of the tree of life by sequencing large numbers of unknown microbial genomes. The group published a study in Nature Biotechnology this week in which they analyzed 1,003 new genomes that were sequenced from bacterial and archaeal organisms.
This latest batch of microbial genomes not only confirms the tremendous genetic diversity of microbes, but adds to the growing catalog of microbe-produced proteins and enzymes that could one day transform medicine, energy production, genetic engineering, and various other fields.
Nikos Kyrpides leads the Genomic Encyclopedia of Bacteria and Archaea (GEBA) initiative at the DOE’s Joint Genome Institute. He explained that the first 20 years of microbial genome sequencing focused on well-known microorganisms like viruses and pathogenic bacteria. In fact, by 2015, 43 percent of all sequenced bacterial genomes were strains from the same 10 pathogenic species.
But that narrow focus ignored large swaths of the phylogenetic family tree that left entire branches without a single representative genome. Armed with radically faster and more powerful sequencing technology, Kyrpides’s group set out to catalog genomes representing the full diversity of microbial life on Earth. In 2009, they published an analysis of the first batch of 56 microbial genomes, in which they identified sequences of microbial DNA that pumped out entirely new proteins and enzymes.
“We saw there’s an enormous amount of discovery that can be done through the study of microbes for which we don’t know anything about.”
“We saw there’s an enormous amount of discovery that can be done through the study of microbes for which we don’t know anything about,” said Kyrpides, who quickly proposed funding for a much larger sequencing effort.
This latest batch of more than 1,000 genomes included 845 “singletons” — the only sequenced representative of their species. Analysis of the genomes also revealed a 10 percent increase in novel protein families.
Jonathan Eisen, an evolutionary biologist at the University of California Davis, helped launch the microbial genome encyclopedia project at the DOE. He said that the value of this open genomic reference library is twofold: first, it provides researchers worldwide with a more accurate catalog of the diversity of life; and second, it identifies new proteins and enzymes that can used for a variety of purposes, from developing new cures for chronic diseases to efficiently generating natural gas from biomass.
Eisen noted that data from the first 56 genomes analyzed in 2009 led to the discovery of new forms of cellulase, the enzyme that breaks down plant material for biofuel production. Researchers also scanned the growing genomic encyclopedia to find novel variants of the Cas9 protein that may improve upon the popular CRISPR gene-editing technology, said Kyrpides.
In its mission to fill the microbial gaps in the tree of life, the DOE team searched high and low for microbes that fell outside of the spotlight. The latest batch of 1,000 bacteria and archaea — primitive single-celled organisms without a nucleus or membrane-bound organelles — were sampled from extreme environments like oil springs, industrial waste sites, and the funkier corners of the human body.
The effort to sequence unknown microbes has already paid off in some appropriately unexpected ways. Eisen points to a 2015 paper that revealed some key differences between the gut microbes of modern Westerners and those living in the digestive tracts of a hunter-gatherer tribe in Peru. One microbe in particular, Treponema, was present in large numbers in the hunter-gatherers but almost non-existent in folks from Oklahoma. The researchers were able to match the mysterious gut microbe’s genome with its closest relative, a Treponoma species found in pigs, because it was already in the DOE encyclopedia.
“Here’s this ostensibly really important member of the human microbiome, at least in these hunter-gatherer populations, that was completely missed by the Human Microbiome Project,” Eisen said, referring to the National Institutes of Health project to sequence the most important “good” and “bad” microbes in the human gut.
Kyrpides recognizes that such a large-scale genome sequencing effort would have been prohibitively expensive and painfully slow even five years ago. But profound improvements in sequencing technology have opened the doors to unfettered exploration of microbial diversity. The key next-generation sequencing platforms used by the DOE group were Illumina and PacBio.
Technological improvements are also revolutionizing the application of this new genomic data, Eisen said. If a bioenergy or biomedicine company wants to experiment with a new protein or enzyme found in the encyclopedia, it no longer has to culture the particular microbe that produces the enzyme or extract and clone its DNA. That’s what the genome encyclopedia is for.
Read more at Discovery News
Jun 12, 2017
A University of Iowa-led team of biologists analyzed the genome of Ambystoma, a six-million-year-old salamander lineage that produces only female offspring. The team found most of its genetic profile is made up of equal contributions from males of three separate salamander species -- Ambystoma laterale, Ambystoma texanum, and Ambystoma tigrinum.
The researchers think the all-female salamander's balanced genome points to the bizarre ways some animals -- from all-female populations of fish, lizards, and others -- can use their genomes to maximize their chances of success.
"We're hypothesizing the successful individuals have balanced gene expression," says Maurine Neiman, associate professor in biology at the UI and an author on the paper, published in the journal Genome Biology and Evolution. "This balance might have been a prerequisite for the emergence and continued success of this particular hybrid lineage."
Sexual reproduction is dominant in the animal world. The unisexual Ambystoma salamander engages in sex, but with a slightly different purpose. When it mates, the female acquires the male's genes and then keeps only some, discarding others. This is known as kleptogenesis, or the theft of genetic material from male donors for reproductive purposes.
The UI researchers wondered how choosy the unisexual female is about which genes it keeps and uses when mating with males from different sexual salamander species. Using a specimen from the lab of Ohio State University biologist and study co-author H. Lisle Gibbs, the team analyzed nearly 3,000 genes in a unisexual female with three genomes (called a triploid). Of that total, they found 72 percent of the genes provided by the three male partners were expressed equally.
In other words, the all-female salamander chose to use roughly the same number of genes from each salamander species.
"It's mostly balanced. The three genomes are mostly being expressed equally in this hybrid," says Kyle McElroy, a graduate student in Neiman's lab and the paper's corresponding author. "What we'd like to find out is how the choosing and using occurs, and how these genes from different sexual salamander species come together to make a successful hybrid."
It could be a case of keeping things simple. McElroy likens it to a sports team having a roster of equally competent players, with no star athlete whose injury would cripple its success.
"If you have a team that's unbalanced and loses a top player, you won't win," says McElroy, a fourth-year graduate student from St. Louis. "But if every player is equal, then you don't lose as much."
So, rather than the female salamander individually selecting genes from the thousands available to her -- a complicated process -- the salamander appears to have found a balanced ratio of genes from the males of the other three species that works for her, and has settled on that.
Read more at Science Daily
Now a technological breakthrough, outlined in a paper published by the journal Nature Chemical Biology, has just been developed that could unlock the floodgates for new drugs originating from fungi. The process involves using genomics and data analytics to capture fungal DNA and then identify promising new chemical molecules that could become the basis of a range of new drugs.
“New chemical matter from the fungal world can now be extracted,” senior author Neil Kelleher, a chemical biologist at Northwestern University, told Seeker. “So it’s like mining for gold, but instead of small labs panning for nuggets, the process can now be industrialized.”
The technology developed by Kelleher, lead author Kenneth Clevenger, and their colleagues consists of a three-step system. First, genomics and molecular biology are used to identify and capture broad portions of fungal DNA known as gene clusters. Next, the gene clusters are placed into a model fungus: Aspergillus nidulans.
Clevenger explained that this fungus “is one of the most studied fungi out there, so we know a lot about it biology and chemistry.” As a result, he continued, scientists can then distinguish with greater ease new molecules from those in the fungus that are already well documented.
The final step is to utilize mass spectrometry and data analytics to analyze the resulting fungal compounds.
The researchers applied the three-step technology to investigate three diverse fungal species, and discovered 17 new compounds from the 56 gene clusters that they screened. Kelleher noted that this is “a great hit rate in the business of natural products discovery.”
The team named one of the new metabolites valactamide A, and it is now the focus of additional study. Co-author Nancy Keller of the University of Wisconsin-Madison said that fungi often produce such metabolites as protectants and weapons from other microbes or environmental stresses.
“Due to these properties,” she said, “many fungal metabolites become very valuable in treating human disease by targeting pathogenic microbes or malfunctioning human enzymes.”
For example, the fungi-sourced lovastatin targets an enzyme — HGM-CoA reductase — found in both humans and fungi. This enzyme is needed to produce cholesterol in humans as well as the fungi version of cholesterol, called ergosterol. When lovastatin interacts with the enzyme in a person, it can lower that individual’s LDL cholesterol (popularly known as the “bad” cholesterol). The drug also has antifungal properties.
“It’s likely that many fungi-sourced compounds with medical potential will be antimicrobial, but based on past history, we can also expect drugs to target the human immune response and high cholesterol, among others,” Clevenger said.
Other tech advances in recent years have led to the realization that good health often has more to do with a well-balanced microbiome than the presence — or absence — of any particular supposed beneficial or detrimental agent.
Read more at Discovery News
Data gathered by NASA’s Curiosity rover over the past five years have allowed scientists to construct a detailed portrait of the history of Gale Crater and the lowermost layers of Mount Sharp where the rover has been traversing. Rocks studied during the mission have shown that this site was once a muddy lakebed, filled with water.
The latest research suggests with even more certainty that this was once likely a habitable environment. The diversity of minerals in the rock samples collected by Curiosity are also revealing details about the ancient environmental changes that occurred as Mars started to shed its atmosphere millions of years ago and much of the water on the planet's surface was lost to space.
“We went to Gale Crater to investigate these lower layers of Mount Sharp that have these minerals that precipitated from water and suggest different environments,” said Elizabeth Rampe, a NASA exploration mission scientist at Johnson Space Center and lead author of a new study, in a press statement. “These layers were deposited about 3.5 billion years ago, coinciding with a time on Earth when life was beginning to take hold. We think early Mars may have been similar to early Earth, and so these environments might have been habitable.”
The researchers looked specifically at four samples that were collected from the lower layers of Mount Sharp using the rover’s drill and studied with the onboard chemistry lab, the Chemistry and Mineralogy (CheMin) instrument. They looked specifically at the mineralogy of a layered mudstone called lacustrine, which is formed by lake sedimentation. (On Earth, lacustrine environments are a major contributor of petroleum source rocks.)
A rock’s various layers can tell the story of the geologic and climate history of Mars, yielding information about the planet’s past likelihood of habitability. Determining what minerals can be found in the layers of Martian sedimentary rock can also yield much data about the environment in which they formed.
The team said that the minerals found in the four different samples vary widely within the various layers of the rocks, which suggests that several different environments were present in ancient Gale Crater. There is evidence for waters with different pH and other varying conditions.
At the base are minerals that are volcanic in origin that are rich in iron and magnesium, similar to basalts in Hawaii. Moving higher in the section, scientists saw more silica-rich minerals. In the Telegraph Peak sample, scientists found minerals similar to quartz. In the Buckskin sample, scientists found tridymite. Tridymite is found on Earth, for example, in rocks that formed from partial melting of Earth’s crust or in the continental crust. Scientists say this is a strange finding because Mars never had plate tectonics.
Additionally, there are different iron-oxide minerals in the samples, reflecting the oxidation of the rock minerals as they reacted with oxygen. This tells scientists the water in the lake changed over time.
In their paper, published in Earth and Planetary Science Letters, the researchers discuss two hypotheses to explain this mineralogical diversity. The lake waters themselves at the base were oxidizing, so either there was more oxygen in the atmosphere or other factors encouraged oxidation.
Another hypothesis is that the groundwater changed over time, and that the environmental conditions present in the lake and in later groundwater were quite different. But both offered liquid water and a chemical diversity that could have been favorable for microbial life.
“We have all this evidence that Mars was once really wet but now is dry and cold,” Rampe said. “Today, much of the water is locked up in the poles and in the ground at high latitudes as ice. We think that the rocks Curiosity has studied reveal ancient environmental changes that occurred as Mars started to lose its atmosphere.”
The question is, how long did the water remain on Mars, and was it long enough for life to flourish?
These findings, along with all of the data gathered during Curiosity’s mission, are helping to give scientists a full picture of ancient Mount Sharp, where the rocks appear to be made from the silt that settled out from the lakes.
Read more at Discovery News